Just had a look at the progress on the Kryptos cipher. The final 97 characters still haven’t been cracked. At the end of last year Jim Sanborn revealed that characters 64-69 decode to ‘BERLIN’. Since all of these characters are in the code, some kind of permutation is still possible. A combination with substitution is of course also a possibility.

OBKRUOXOGHULBSOLIFBBWFLRVQQPRNGKSSOTWTQSJQSSEKZZWATJKLUDIAWINFBNYPVTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR

Assuming a permutation we can check the possible positions and jumps for ‘BERLIN’. For example the possible distances from a B in the code to an E, then the possible distances from E to an R, etcetera. The ‘nicest’ sequence starts at position 19: 73-8-8-73-73, especially when you realize that modulo 97 you can rewrite 73 as -24, or 3 times 8. Unfortunately the obvious extrapolations don’t give any meaningful results.